[PATCH app/xev] parse state to describe in-use modifiers

[Benjamin Elijah Griffin]

Example for <ctrl-c>:

KeyPress event, serial 28, synthetic NO, window 0x2a00001,
    root 0x176, subw 0x0, time 605237548, (-825,547), root:(303,559),
    state 0x4, keycode 54 (keysym 0x63, c), same_screen YES,
    modifier: control
    XLookupString gives 1 bytes: (03) ""
    XmbLookupString gives 1 bytes: (03) ""
    XFilterEvent returns: False

Signed-off-by: Benjamin Elijah Griffin <freedesktop at eli.users.panix.com>
---
 configure.ac |  2 +-
 xev.c        | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index 6adaa43..72d22b4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -22,7 +22,7 @@ dnl Process this file with autoconf to create configure.

 # Initialize Autoconf
 AC_PREREQ([2.60])
-AC_INIT([xev], [1.2.3],
+AC_INIT([xev], [1.2.4],
         [https://gitlab.freedesktop.org/xorg/app/xev/issues], [xev])
 AC_CONFIG_SRCDIR([Makefile.am])
 AC_CONFIG_HEADERS([config.h])
diff --git a/xev.c b/xev.c
index 4c6115f..f5cc32b 100644
--- a/xev.c
+++ b/xev.c
@@ -106,6 +106,43 @@ dump(char *str, int len)
 }

 static void
+show_Modifiers(int state)
+{
+    int i, smask, sflag = 1;
+
+    printf("    modifier: ");
+    if (state & sflag)
+        printf("shift ");
+    sflag <<= 1;
+    if (state & sflag)
+        printf("lock ");
+    sflag <<= 1;
+    if (state & sflag)
+        printf("control ");
+    sflag <<= 1;
+
+    for (i = 3; i < 8; i++) {
+       if (state & sflag)
+            printf("mod%d ", i - 2);
+        sflag <<= 1;
+    }
+
+    /* Mouse buttons are also modifiers */
+    for (i = 8; i < 13; i++) {
+       if (state & sflag)
+            printf("Button%d ", i - 7);
+        sflag <<= 1;
+    }
+
+    /* Any bits in state that we didn't already test? */
+    smask = ~ (sflag - 1);
+    if (state & smask)
+        printf("other: 0x%x", (state & smask));
+
+    printf("\n");
+}
+
+static void
 do_KeyPress(XEvent *eventp)
 {
     XKeyEvent *e = (XKeyEvent *) eventp;
@@ -151,6 +188,10 @@ do_KeyPress(XEvent *eventp)
     printf("    state 0x%x, keycode %u (keysym 0x%lx, %s), same_screen %s,\n",
            e->state, e->keycode, (unsigned long) ks, ksname,
            e->same_screen ? Yes : No);
+    if (e->state) {
+        show_Modifiers(e->state);
+    }
+
     if (kc_set && e->keycode != kc)
         printf("    XKeysymToKeycode returns keycode: %u\n", kc);
     if (nbytes < 0)
@@ -198,6 +239,9 @@ do_ButtonPress(XEvent *eventp)
            e->root, e->subwindow, e->time, e->x, e->y, e->x_root, e->y_root);
     printf("    state 0x%x, button %u, same_screen %s\n",
            e->state, e->button, e->same_screen ? Yes : No);
+    if (e->state) {
+        show_Modifiers(e->state);
+    }
 }

 static void
@@ -215,6 +259,9 @@ do_MotionNotify(XEvent *eventp)
            e->root, e->subwindow, e->time, e->x, e->y, e->x_root, e->y_root);
     printf("    state 0x%x, is_hint %u, same_screen %s\n",
            e->state, e->is_hint, e->same_screen ? Yes : No);
+    if (e->state) {
+        show_Modifiers(e->state);
+    }
 }

 static void
--
2.7.4